Titanium’s “detach from Market” hasn’t worked for over a year simply because Google Play update is ahead of the game as far as the 'detach from Market' pedlars are concerned.
One method is to freeze Market Updater, uninstall the offending Google Play update, and then use Titanium’s ‘detach from Market’. … I haven’t tried it because I’m not too keen on the pre-update Market.
What annoys me is that 'detach from Market' is still an option in Titanium - it’s misleading and mis-selling. It would’ve been better if I threw the purchase price (not ‘donate’ as the dev euphemistically calls it) to a street-beggar, as it was my main reason for buying the damn thing in the first place.